Blade drive device

ABSTRACT

A blade drive device includes: a blade; a drive source that drives the blade; and a chassis that has an opening opened and closed by the blade and that houses the blade and the drive source. The drive source includes: a rotor that is rotatably supported; a stator around which a coil for excitation is wound and which applies a rotational force to the rotor. The stator is arranged to surround a periphery of the opening and has a rectangular shape.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims priority to International Patent Application No. PCT/JP2008/062859 filed on Jul. 16, 2008, which claims priority to Japanese Patent Application No. 2007-233367 filed on Sep. 7, 2007, subject matter of these patent documents is incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to blade drive devices.

2. Description of the Related Art

Generally, a blade drive device for a camera includes: a board having an opening; a blade opening and closing the opening; and a drive source, such as an actuator, driving the blade (see Japanese Unexamined Patent Application Publication No. 2006-11293). In such a blade drive device, a high-power actuator is employed, so that a shutter speed can be increased.

However, the high-power actuator has a large size. Thus, there is a problem that the size of the blade drive device is also increased by employing such an actuator.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a blade drive device which is reduced in size and has an improved shatter speed.

According to an aspect of the present invention, there is provided a blade drive device including: a blade; a drive source that drives the blade; and a chassis that has an opening opened and closed by the blade and that houses the blade and the drive source, the drive source including: a rotor that is rotatably supported; a stator around which a coil for excitation is wound and which applies a rotational force to the rotor, and the stator being arranged to surround a periphery of the opening and having a rectangular shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a configuration of a blade drive device according to a first embodiment;

FIG. 2 is a cross-sectional view taken along a line A-A in FIG. 1;

FIG. 3 is a cross-sectional view taken along a line B-B in FIG. 1;

FIG. 4 is a rear view of a blade drive device according to the first embodiment;

FIG. 5 is an enlarged view of a connecting portion of iron pieces, as illustrated in FIG. 2;

FIG. 6 is a cross-sectional view of a filling portion;

FIG. 7 is an exemplary cross-sectional view of a snap fitting structure;

FIG. 8 is a front view of a configuration of a blade drive device according to a second embodiment;

FIG. 9 is a front view of the blade drive device according to the second embodiment with a flexible print substrate being omitted;

FIG. 10 is a cross-sectional view taken along a line C-C in FIG. 8;

FIG. 11 is a cross-sectional view taken along a line D-D illustrated in FIG. 8;

FIG. 12 is a front view of a variation of the blade drive device according to the first embodiment; and

FIG. 13 is a front view of a variation of the blade drive device according to the second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A description will be given of embodiments according to the present invention with reference to the drawings.

First Embodiment

FIG. 1 is a front view of a configuration of a blade drive device according to a first embodiment. FIG. 2 is a cross-sectional view taken along a line A-A in FIG. 1. FIG. 3 is a cross-sectional view taken along a line B-B in FIG. 1. FIG. 4 is a rear view of a blade drive device according to the first embodiment. The blade drive device according to the first embodiment includes: an upper case 10; a lower case 20; a blade 30; a rotor 40; iron pieces 50, 60L, and 60R; coils 70L and 70R; and a flexible printed circuit board 80.

The upper and lower cases 10 and 20 serve as a chassis that houses the blade 30, the rotor 40, the iron pieces 50, 60L, and 60R, and a part of the flexible printed circuit board 80, as illustrated in FIGS. 2 and 3. The upper and lower cases 10 and 20 are made of a synthetic resin. The upper case 10 is thicker than the lower case 20. The blade drive device according to the first embodiment is attachable to an image pickup apparatus or a lens drive apparatus so that the upper case 10 faces the object side and the lower case 20 faces an image pickup element such as a CCD. The upper and lower cases 10 and 20 are respectively provided with openings 11 and 21 for shooting. A slope portion 12 is provided around the opening 11, as illustrated in FIG. 3. Additionally, the upper case 10 is indicated by a broken line in FIG. 1.

The blade 30 is made of a synthetic resin. The blade 30 is supported to open and close the openings 11 and 21. The blade 30 swings together with the rotor 40. The blade 30 illustrated in FIG. 1 is positioned at a receded position, which is receded from the openings 11 and 21, and is causing the openings 11 and 21 to be fully opened.

The rotor 40 is magnetized with differential magnetic poles in the circumferential direction, and is rotatably supported within the upper and lower cases 10 and 20 serving as a chassis. The rotor 40 has a cylindrical shape. A stopper member 41 is fitted into an inner circumference of the rotor 40. Thus, the rotor 40 rotates in conjunction with the stopper member 41.

The stopper member 41 has a substantially cylindrical shape made of a synthetic resin. The inner circumference of the stopper member 41 is slidably engaged with a rotor supporting shaft 13 extending in the optical path direction, from the upper case 10. In this manner, the rotor 40 is rotatably supported. As illustrated in FIG. 3, the stopper member 41 is provided with a pin portion 411 extending radially outward from a bottom of the stopper member 41. The pin portion 411 extends radially outward beyond the outer circumferential surface of the rotor 40. Additionally, the blade 30 is engaged with the bottom portion of the stopper member 41. The rotation of the stopper member 41 allows the blade 30 to swing about the rotor supporting shaft 13. Therefore, the rotation of the rotor 40 swings the blade 30 to open and close the openings 11 and 21. Additionally, the upper case 10 is provided with restricting pins 14L and 14R contactable with the pin portion 411, as illustrated in FIGS. 1 and 3. By causing the pin portion 411 to be contact with the restricting pins 14L and 14R, the rotational range of the rotor 40 is restricted. Thus, the swinging range of the blade 30 is also restricted. Further, the lower case 20 is provided with a releasing hole 24 for receiving the thickness of the pin portion 411, as illustrated in FIG. 4. Furthermore, the rotor supporting shaft 13 is engaged with an engagement hole provided in the lower case 20.

The iron pieces 50, 60L, and 60R are arranged along the inner side surfaces of the upper and lower cases 10 and 20. The iron pieces 50, 60L, and 60R surround a substantially entire periphery of the openings 11 and 21 except for the rotor 40. The iron pieces 50, 60L, and 60R are connected to one another. The iron piece 50 has a substantially lateral U shape, as illustrated in FIG. 1. The iron pieces 60L and 60R are respectively connected to end portions of the iron piece 50, as illustrated in FIGS. 1 and 2. The iron pieces 60L and 60R are respectively provided with magnetic poles 62L and 62R facing the outer circumferential surface of the rotor 40. Specifically the iron pieces 60L and 60R are connected to end portions of two opposed sides of the iron piece 50, and then orthogonally arranged to the two opposed sides. The iron pieces 60L and 60R are arranged to face each other. In addition, the iron piece 60L is omitted in FIG. 2.

The iron piece 50 has right-and-left arm portions around which coils 70L and 70R are respectively wound. The coils 70L and 70R are provided for exciting the iron pieces 50, 60L, and 60R. The magnetic poles 62L and 62R are excited to be different poles by energization of the coils 70L and 70R, effecting a magnetically attractive force or magnetically repulsive force on the rotor 40. Therefore, the rotational force is given on the rotor 40. In other words, the iron pieces 50, 60L, and 60R entirely serve as a stator giving the rotational force to the rotor 40. Accordingly, the rotor 40, the iron pieces 50, 60L, and 60R, and the coils 70L and 70R serve as an actuator, which is a drive source driving the blade 30.

Additionally, all of the iron pieces 50, 60L, and 60R are arranged in a substantially rectangular shape when viewed in the optical path direction. Accordingly, the upper and lower cases 10 and 20 each are formed in a rectangular shape when viewed in the optical path direction. The blade 30 is arranged at such a position as to be surrounded by the iron pieces 50, 60L, and 60R. Further, each of the iron pieces 50, 60L, and 60R has a flat shape in the optical axis direction. Furthermore, the coils 70L and 70R are wound around the iron piece 50, whereas the coil is not wound around the iron pieces 60L and 60R. The iron pieces 60L and 60R each has an identical shape.

As illustrated in FIGS. 1, 3, and 4, a flexible printed circuit board 80 (hereinafter referred to as a FPC) is inserted into the upper and lower cases 10 and 20. The FPC 80 has flexibility. The FPC 80 is provided with solder lands 81L, 81R, 82L, and 82R for energizing the coils 70L and 70R at its surface facing the lower case 20. The both ends of the coil 70L are respectively connected to the solder lands 81L and 82L. Similarly, the both ends of the coil 70R are respectively connected to the solder lands 81L and 82L. The solder lands 81L, 81R, 82L, and 82R are housed within the upper and lower cases 10 and 20 serving as a chassis, and are surrounded by the iron pieces 50, 60L, and 60R. The FPC 80 is provided with an attachment hole 87. As illustrated in FIGS. 1 and 3, a supporting pin 17 formed in the upper case 10 is inserted into the attachment hole 87. Further, the supporting pin 17 is engaged with an engagement hole 27, as illustrated in FIGS. 3 and 4. Therefore, the supporting pin 17 functions to connect with the engagement hole 27, and also functions to fix the FPC 80 at a given position.

Additionally, as illustrated in FIG. 3, the FPC 80 is inserted into the upper and lower cases 10 and 20 via an insert hole 18 formed in the upper case 10. The FPC 80 is fixed along the inner surface of the upper case 10, via a carve portion 88 before reaching the iron piece 50.

Next, a description will be given of the iron pieces 50, 60L, and 60R. FIG. 5 is an enlarged view of a connecting portion of the iron pieces 50 and 60R, as illustrated in FIG. 2. As illustrated in FIG. 5, at the connecting portion of the iron pieces 60R and 50, thin portions 51R and 61R are in contact with each other. The thin portions 51R and 61R are thinner than another portion of the iron pieces 50 and 60R, respectively. In addition, the thin portions 51R and 61R are respectively formed with fitting holes 55R and 65R. A fixing pin 15R, which is formed in the upper case 10, is inserted into the fitting holes 55R and 65R. Further, an end portion of the fixing pin 15R is pressure bonded with a bottom edge surface of the iron pieces 50R by thermal caulking, whereby the thin portions 51R and 61R are in pressure contact with each other. This configuration also applies to the fitting holes 55L and 65L, and a fixing pin 15L.

Furthermore, as illustrated in FIG. 5, the upper case 10 is provided with an engagement pin 16R adjacent to the fixing pin 15R. The engagement pin 16R is engaged with engagement recess portions 56R and 66R, which are respectively provided in the thin portions 51R and 61R. Unlike the fitting holes 55R and 65R, the engagement recess portions 56R and 66R are cut out at peripheral surfaces of the iron pieces 50 and 60R in the optical axis direction. This configuration also applies to an engagement pin 16L, and engagement recess portions 56L and 66L.

Furthermore, as illustrated in FIG. 4, filling portions which are filled with adhesive materials A are provided at two corner portions on a diagonal line of the upper and lower cases 10 and 20. FIG. 6 is a cross-sectional view of the filling portion. As illustrated in FIGS. 4 and 6, the filling portion is defined by an embankment portion 19, a bending portion 29, and an inner peripheral surface of the corner portion of the upper case 10. The embankment portion 19, having a projective shape, is raised toward the lower case 20 from the upper case 10. The bending portion 29 is carved toward the upper case 10 at an outer edge portion of the lower case 20. The upper and lower cases 10 and 20 are fixed by the adhesive material a filled in the filling portions.

Next, a belief description will be given of an assembling method of the blade drive device according to the first embodiment. Firstly, the rotor 40, the stopper member 41, and the blade 30 are integrated with the inner side of the upper case 10 facing upwardly and are then engaged with the rotor supporting shaft 13. Next, the iron piece 60R is arranged inside of the upper case 10 so as to respectively engage the fixing pin 15R and the engagement pin 16R with the fitting hole 65R and the engagement recess portion 66R. In the same manner, the iron piece 60L is also arranged. In addition, the iron piece 60R is attached such that the fixing pin 15R and the engagement pin 16R are engaged with the fitting hole 65R and the engagement recess portion 66R respectively at the same time. The engagement pin 16R serves to prevent the iron piece 60R from rotating about the fixing pin 15R. Therefore, the iron piece 60R is positioned relative to the upper case 10. Herein, the iron piece 60R may be attached such that the fixing pin 15R and the engagement pin 16R are in pressure contact with each other. In this case, the iron piece 60R having a desirable clearance with respect to the rotor 40 can be securely fixed to the upper case 10. The fitting hole 65L and the engagement recess portion 66L of the iron piece 60L, and the fixing pin 15L and the engagement pin 16L are provided in the same manner as the above arrangements.

Next, the FPC 80 is attached into the upper case 10 such that the solder land 81 or the like faces the inside of the upper case 10 and the supporting pin 17 is fitted into the attachment hole 87. Then, the iron piece 50 wound with the coils 70L and 70R is attached to the inner periphery of the upper case 10 such that the fixing pins 15L and 15R are respectively fitted into the fitting holes 55L and 55R, and the engagement pins 16L and 16R are respectively engaged with the engagement recess portions 56L and 56R. In this case, the iron piece 50 is attached to the upper case 10 such that the thin portion 51R of the iron piece 50 and the thin portion 61R are overlapped, and the thin portions 51L and 61R are overlapped. Next, the end portions of the fixing pins 15L and 15R are melted by thermal caulking, so the end portions of the fixing pins 15L and 15R and the outer surface of the iron piece 50 are welded. Further, in order to further securely fix the iron piece 50 to the upper case 10, the end portions of the engagement pins 16L and 16R may be melted by thermal caulking so as to weld with the outer surface of iron piece 50. Next, the lower case 20 is assembled into the upper case 10 such that the supporting pin 17 is engaged with the engagement hole 27 and that the rotor supporting shaft 13 is engaged with an engaging hole according to the rotor supporting shaft 13. Then, the adhesive material A is filled into the filling portion to bond the upper and lower cases 10 and 20. As mentioned above, the blade drive device according to the first embodiment is assembled.

Next, a description will be mainly given of a structure for improving handling ability and for maintaining the reduced thickness in the optical axis direction, according to the first embodiment of the blade drive device. A conventional blade drive device includes: a base plate having an opening; a blade, and an actuator for driving the blade. The actuator is typically arranged on an edge portion, of the base plate, receded away from the opening. Thus, a stator is also arranged on the edge portion of the base plate. In a case where the stator is arranged in such a manner, since the base plate is exposed from the outer periphery of the blade drive device and the base plate is typically formed into a thin shape, the base plate may be bended depending on the handling thereof when the blade drive device is assembled or when the assembled blade drive device is installed into an image pickup apparatus or a lens drive apparatus.

However, in the blade drive device according to the present embodiment, as mentioned above, the iron pieces 50, 60L, and 60R serving as the stator are integrated, and are formed along the inner side surfaces of the upper and lower cases 10 and 20. Therefore, even when the blade drive device is tightly held at its outer periphery, the upper and lower cases 10 and 20 are hardly bent. Accordingly, the handling ability is improved when the blade drive device is assembled and the blade drive device is installed into the mobile phone or the like.

Further, since the iron pieces 50, 60L, and 60R are integrated and are shaped along the inner peripheries of the upper and lower cases 10 and 20, the operation of the blade 30 is ensured even when an impact is applied to the blade drive device from its external. Therefore, the impact resistance is improved. In particular, when the impact is applied to the side of the blade drive device, the impact resistance is improved. Further, the optical axis direction thickness of the upper and lower cases 10 and 20, which serve as the chassis, corresponds to the thicknesses of the coils 70L and 70R, as illustrated in FIG. 2. Typically, the coil for exciting the stator is thicker than any other parts in the blade drive device. Therefore, the thickness of the upper and lower cases 10 and 20 corresponds to the thicknesses of the coils 70L and 70R, thereby improving the handling ability and maintaining the reduced thickness in the optical axis direction.

Additionally, as illustrated in FIG. 1, the solder lands 81R, 81L, 82R, and 82L provided in the FPC 80 are housed within the upper and lower cases 10 and 20, and are surrounded by the iron pieces 50, 60L, and 60R. With such a configuration, when the blade drive device is assembled, the coil break due to deflecting of the blade drive device can be prevented, and the handling ability is improved. Further, the FPC 80 is inserted into the upper and lower cases 10 and 20 via these side surfaces, thereby maintaining the reduced thickness of the blade drive device in the optical axis direction. In addition, the conventional blade drive device includes a drive pin, which is attached to the rotor, which protrudes outwardly, and which bends downwardly in the optical axis direction. Such a drive pin is engaged with an engagement hole formed on a blade to drive the blade. In this manner, the drive pin bends downwardly in the optical axis direction. This is one of factors that increase the thickness of the conventional blade drive device in the optical axis direction. However, in the blade drive device according to the first embodiment, since the blade 30 is attached to the rotor 40, as illustrated in FIG. 3, the reduced thickness can be maintained in the optical axis direction. Furthermore, this eliminates the drive pin for transmitting the driving force from the rotor to the blade, thereby decreasing the number of the parts.

In addition, the blade 30 is directly fixed to the stopper member 41, as illustrated in FIG. 3. In the present embodiment, the blade 30 and the stopper member 41 are separately provided. However the blade 30 and the stopper member 41 may be integrated. Therefore, the number of the parts can be further reduced. In addition, in the present embodiment, the rotor supporting shaft 13, which serves as a spindle for supporting the rotation of the rotor 40, is integrally formed in the upper case 10. However, the invention is not limited to this configuration. For example, a rotor shaft which rotates in conjunction with the rotor may be employed. In this case, the blade 30 may be directly fixed to the rotor shaft, or the blade 30 may be integrally formed with the rotor shaft.

Returning to FIG. 6, the filling portions, for filing the adhesive material A for fixing the upper and lower cases 10 and 20, are provided in the upper and lower cases 10 and 20. In this manner, the upper and lower cases 10 and 20 are fixed by the adhesive material A. In the conventional blade drive device, a projection, which is projected in the optical axis direction, is formed in one of the upper and lower cases 10 and 20. A fitting hole, which is fitted with the projection, is formed in the other of the upper and lower cases 10 and 20. The end portion of the projection, which is fitted into the fitting hole, is welded by thermal caulking, thus the both are fixed. In this manner, the fixation by thermal caulking causes the end portion of the projection to be slightly melted. This is one of factors that increase the thickness in the optical axis direction. However, as the blade drive device according to the present embodiment, the upper and lower cases 10 and 20 are fixed by an adhesive material, the reduced thickness can be maintained in the optical axis direction.

Further, although the upper and lower cases 10 and 20 are fixed by the adhesive material, the present invention may employ another configuration. For example, the upper and lower cases 10 and 20 may be fixed by snap fitting. FIG. 7 is an exemplary cross-sectional view of a snap fitting structure. As illustrated in FIG. 7, the upper and lower cases 10 and 20 may be respectively provided with an engagement piece 19 s and an engagement hole 29 s corresponding to each other such that the engagement piece 19 s and the engagement hole 29 s do not exceed the thickness in the optical axis direction when the upper and lower cases 10 and 20 are assembled. In this case, the space where the adhesive material is filled is unnecessary, thereby maintaining the reduced thickness in the optical axis direction and also reducing the size in the planar direction perpendicular to the optical axis direction.

Additionally, since the iron pieces 50, 60L, and 60R, serving as the stator, have flat shapes in the optical axis direction, as illustrated in FIGS. 2 and 3, the reduced thickness can be maintained in the optical axis direction. In particular, as illustrated in FIG. 5, in the connecting portion of the iron piece 50 and the iron pieces 60L and 60R, the thin portions 51L and 51R of the iron piece 50 are respectively overlapped with the thin portions 61L and 61R in the optical axis direction, when the iron pieces 60L and 60R are connected to the iron piece 50. Therefore, the reduced thickness can be maintained in the optical axis direction.

As mentioned above, each of the upper and lower cases 10 and 20 has a rectangular shape as seen in the optical axis direction, and the iron pieces 50, 60L, and 60R are arranged to have a rectangular shape, as seen in the optical axis direction so as to correspond to the shapes of the upper and lower cases 10 and 20. With such a configuration, in the case where the rectangular shape is formed, the area where the solder lands 81R, 81L, 82R, and 82L are formed is ensured widely, as compared with a case where a circular shape is formed as seen in the optical axis direction. Therefore, the space for arranging components can be effectively used. Further, the handling is facilitated after the assembly is finished.

Next, a description will be given a structure for positioning and fixing the drive source relative to the upper case 10. As illustrated in FIGS. 1 and 2, the iron pieces 50, 60L, and 60R serving as the stator are fitted onto the fixing pins 15R and 15L and the engagement pins 16R and 16L so as to be positioned and fixed. Conventionally, the outer periphery of the stator is in pressure contact with positioning pins provided on a board to position and fix the stator. However, when such positioning pins, which are in pressure contact with the outer periphery of the stator, are provided on the board or the like, the size cannot be reduced in the planar direction perpendicular to the optical axis direction. In the blade drive device according to the first embodiment, the fitting hole 55R or the likes, which fitted onto the fixing pin 15R or the like, is provided in the iron piece 50 or 60R. Therefore, the pins, which come into contact with the periphery of the stator, can be eliminated, thereby reducing the size of the upper and lower cases 10 and 20 in the planar direction. Accordingly, the size of the blade drive device can be reduced in the planar direction.

Further, as illustrated in FIG. 2, the end portion of the fixing pin 15R is thermally caulked. This securely fixes the iron pieces 50 and 60R on the upper case 10. In addition, since the fixing pin 15R is fitted into the fitting hole 55R of the iron piece 50 and the fitting hole 65R of the iron piece 60R, even when the stator is composed of plural iron pieces, the increase in the number of the parts can be prevented, and the size can be reduced in the planar direction.

Next, regarding the blade drive device according to the first embodiment, a description will be given of a structure for improving the shutter speed while the smaller size is maintained.

As mentioned above, the iron pieces 50, 60L, and 60R are connected to each other and arranged to surround substantially the entire peripheries of the openings 11 and 21. With such an arrangement, the total length of the iron pieces 50, 60L, and 60R serving as the stator can be ensured, and the number of the turns of the coils 70L and 70R can be increased. Therefore, the output power of the rotor 40 is increased and the shutter speed becomes faster. In addition, the iron pieces 50, 60L, and 60R are arranged to surround the substantially entire peripheries of the openings 11 and 21, thereby maintaining the small size of the entire iron pieces 50, 60L, and 60R in the planar direction perpendicular to the optical axis direction.

In addition, the iron pieces 50, 60L, and 60R are formed into a substantially rectangular shape as a whole, thus making its linear portion as long as possible. It is therefore possible to wind the coils 70L and 70R in a great number of turns around the linear portion where the winding is made easy. Moreover, the coils 70L and 70R are wound respectively around two opposed sides of the iron piece 50, thereby increasing the number of the turns of the coil. Also, the rotor 40 is located at a center portion of one side of the rectangle. When the rotor 40 is located at such a position, it is suitable for the coils 70L and 70R are suited to be respectively wound around two opposing sides of the iron piece 50.

In addition, when the stator is integrally formed as the conventional stator and is formed into a complicated shape such that the openings 11 and 21 are surrounded as the blade drive device according to the present embodiment, the winding of the coil around the stator may become difficult. However, the stator, which is employed in the blade drive device according to the present embodiment, is composed of the iron pieces 50, 60L, and 60R which are connected, as mentioned above. Therefore, the coils 70L and 70R are wound around the iron piece 50 before the iron pieces 50, 60L, and 60R are connected, and then they are connected, thereby improving the winding workability.

Second Embodiment

Next, a description will be given of a blade drive device according to a second embodiment with reference to the drawings. Additionally, in the blade drive device according to the second embodiment, components that are similar to those of the first embodiment will be denoted by the same reference numerals as used in connection with the first embodiment, and a detailed description of such components will be omitted.

FIG. 8 is a front view of a configuration of the blade drive device according to the second embodiment. FIG. 9 is a front view of the blade drive device according to the second embodiment with a flexible print substrate being omitted. FIG. 10 is a cross-sectional view taken along a line C-C in FIG. 8.

As illustrated in FIGS. 8 and 9, a rotor 40 a is located at a corner portion of upper and lower cases 10 a and 20 a each has a rectangular shape as seen in the optical axis direction. Additionally, iron pieces 50La and 50Ra serve as a stator and each has an identical L shape. The iron pieces 50La and 50Ra are arranged to be a rectangular shape, to surround the periphery of openings 11 a and 21 a, and to be along inner side surfaces of the upper and lower cases 10 a and 20 a. One ends of the iron pieces 50La and 50Ra are respectively provided with magnetic poles 52La and 52Ra which face the rotor 40 a. Further, the other ends of the iron pieces 50La and 50Ra are connected to each other. The iron pieces 50La and 50Ra are respectively provided with fitting holes 55La and 55Ra, which are respectively engaged with fixing pins 15La and 15Ra formed in the upper case 10 a. The fixing pins 15La and 15Ra are provided near a stopper member 41 a.

A coil bobbin 90 a is assembled onto the iron pieces 50La and 50Ra. The coil bobbin 90 a is made of a synthetic resin. As illustrated in FIGS. 8 and 9, the coil bobbin 90 a includes: two arm portions around which the coils 70La and 70Ra are respectively wound; flange portions 91La and 92La provided at both ends of one of the two arm portions; and the flange portions 91Ra and 92Ra are provided at both ends of the other of the two arm portions. As illustrated in FIG. 9, the flange portions 91La and 91Ra are respectively provided with terminal portions 94La and 94Ra for respectively winding ends of the coils 70La and 70Ra. Herein, the coils 70La and 70Ra are composed of a single wire. This wire is connected to solder lands 81 a and 82 a formed on a FPC 80 a, and is indicated by a dashed line in FIG. 8. Further, the coil bobbin 90 a is provided with a thin portion 93 a connecting the flange portions 92La and 92Ra. The thin portion 93 a is thinner than other portions such as the flange portion 92La, and is bendable. The coil bobbin 90 a is bended via the thin portion 93 a such that the flange portions 92La and 92Ra are perpendicular to each other, as illustrated in FIGS. 8 and 9.

Further, the FPC 80 a is provided with a relief opening 86 a for ensuring an optical path passing through the openings 11 a and 21 a, as illustrated in FIG. 8. The FPC 80 a is provided with a relief opening 84 a for preventing the interference with the rotation of the rotor 40 a. The FPC 80 a are provided with through holes 85La and 85Ra through which the fixing pins 15La and 15Ra are penetrated. FIG. 11 is a cross-sectional view taken along a line D-D illustrated in FIG. 8. As illustrated in FIG. 11, the FPC 80 a is inserted into the upper and lower cases 10 a and 20 a via an insert hole 18 a formed in the upper case 10 a. The FPC 80 a is bended at a bending portion 88 a and arranged along the inner surface of the lower case 20 a. Moreover, the solder lands 81 a and 82 a are arranged within the upper and lower cases 10 a and 20 a to be surrounded by the iron pieces 50La and 50Ra.

Further, as illustrated in FIG. 11, the fixing pin 15La is fitted into the fitting hole 55La formed in the iron piece 50La, an end portion of the fixing pin 15La is fixed in the upper case 10 a by thermal caulking. This configuration also eliminates a positioning pin which abuts with the periphery of the stator, thereby maintaining the small sizes of the upper and lower cases 10 a and 20 a in the planar direction. Accordingly, the small size of the blade drive device in the planar direction can be maintained. Additionally, the fixing pin 15La may be press fitted into the fitting hole 55La. In this case, the iron piece 50La can be securely fixed to the upper case 10 with a desirable certain clearance between the iron piece 50La and the rotor 40 a.

Furthermore, the blade 30 a is fixed to the stopper member 41 a, and the stopper member 41 a is rotated in conjunction with the rotor 40 a, as illustrated in FIG. 10. That is, the blade 30 a is attached to the rotor 40 a via the stopper member 41 a. Also, referring to FIG. 10, thin portions 51La and 51Ra are formed on the connecting portions of the iron pieces 50La and 50Ra, respectively. Further, stage portions 16 a and 26 a for supporting this connecting portion are respectively formed in the upper and lower cases 10 a and 20 a. The stage portions 16 a and 26 a respectively abut with the upper surface of the thin portion 51La and the lower surface of the thin portion 51Ra. In addition, the coil bobbin 90 a and the coil 70La are omitted in FIG. 10.

The blade 30 a illustrated in FIG. 9 is positioned at a receded position in which the blade 30 a is receded from the openings 11 a and 21 a. The blade 30 a in the receded position is arranged to partially overlap the iron piece 50Ra in the optical path direction. In more details, the blade 30 a is arranged between the iron piece 50Ra and the lower case 20 a in the optical path direction. With such a configuration, the small size in the planar direction can be maintained. Furthermore, as illustrated in FIG. 9, both of the coils 70Ra and 70La are wound in such a position not to interfere with the blade 30 a positioned at the receded position. Accordingly, the small size in the planar direction can be maintained.

Moreover, the coil bobbin 90 a is bendable via the thin portion 93 a, as mentioned above. Even when the stator has a rectangular shape in this manner, the coil can be wound around two sides, which do not oppose to each other, of the stator having the rectangular shape. Therefore, the number of the turns of the coil can be increased by means of the single coil bobbin 90 a.

Next, a description will be given of a variation of the blade drive device according to the first embodiment with reference to FIG. 12. FIG. 12 is a front view of the variation of the blade drive device according to the first embodiment. FIG. 12 corresponds to FIG. 1. As illustrated in FIG. 12, a control IC 100, for controlling current in the coils 70L and 70R, is mounted on a FPC 80A. The control IC 100 is mounted on a surface, of the FPC 80A, facing the lower case 20. In this manner, the control IC 100 is also mounted to be surrounded by the iron pieces 50, 60L, and 60R, thereby improving the handling ability of the blade drive device. Also, the control IC 100 is housed within the upper and lower cases 10 and 20, thereby making the blade drive device and the control IC 100 into a single unit, and thereby making the handling of the blade drive device easy. Further, the space within an external device equipped with the blade drive device can be effectively used.

Next, a description will be given of a variation of the blade drive device according to the second embodiment with reference to FIG. 13. FIG. 13 is a front view of a variation of the blade drive device according to the second embodiment. FIG. 13 corresponds to FIG. 8. As illustrated in FIG. 13, a control IC 100 a, for driving the rotor 40 a, is mounted on a FPC 80Aa. The control IC 100 a is also mounted on a surface, of the FPC 80Aa, facing a lower case 20 a. With such a configuration, the handling ability of the blade drive device is also improved. Further, the blade drive device and the IC 100 a can be integrated into a single unit, thereby making the handling of the blade drive device easy and effectively using space within an external apparatus equipped with the blade drive device.

While the preferred embodiments of the present invention have been illustrated in detail, the present invention is not limited to the above-mentioned embodiments, and other embodiments, variations and modifications may be made without departing from the scope of the present invention.

The blade defines the fully open and close states. However, the blade may adjust the opening rate of the opening. Plural blades may be provided.

The embodiments have illustrated the blade 30 made of a synthetic resin. However, the blade 30 may be made of a typically antireflective film of a light shielding film, like a somablack film (Somar Corporation), for example.

Additionally, plural motors may be provided. For example, as described in the second embodiment, when the two iron pieces each has a L shape, the two rotors are arranged on a diagonal line with the opening set as a center.

The second embodiment has illustrated the configuration in which the iron pieces 50La and 50Ra are supported by the stage portions 16 a and 26 a. However, a fixing pin formed in the upper case may be fitted into the fitting holes formed in the iron pieces 50La and 50Ra, and then an end portion of the fixing pin may be fixed to the fitting holes by thermal caulking. Alternately, by pressure fitting the fixing pin into the fitting hole, the iron pieces 50La and 50Ra may be securely fixed to the upper case.

The second embodiment has illustrated the terminal portions 94La and 94Ra, around which the end portions of the coils 70La and 70Ra are respectively wound, are provided in the flange portions 91La and 91Ra of the coil bobbin 90 a, respectively. However, the coil bobbin without the terminal portions 94La and 94Ra may be employed.

Further, a sheet of a ND filter may cover the opening.

Finally, several aspects of the present invention are summarized as follows.

According to an aspect of the present invention, there is provided a blade drive device including: a blade; a drive source that drives the blade; and a chassis that has an opening opened and closed by the blade and that houses the blade and the drive source, the drive source including: a rotor that is rotatably supported; a stator around which a coil for excitation is wound and which applies a rotational force to the rotor, and the stator being arranged to surround a periphery of the opening.

With such a configuration, the stator is arranged to surround the periphery of the opening, reducing the size of the blade drive device in the planar direction perpendicular to the optical axis direction, and ensuring the entire length of the stator. This increases the number of coil turns. Therefore, the blade drive device can be reduced in size and the shutter speed can be improved. Further, since the blade and the drive source are housed in the chassis, the blade drive device can be made to be a single unit. Thus, this facilitates an assembling workability of this blade drive device assembled into a variety of lens drive devices or the like.

In the above configuration, the stator may have a rectangular shape.

The stator has a rectangular shape, thereby making one side of the stator as long as possible. Thus, the coil can be wound around a linear portion, around which the coil is readily wound, in such a manner that the number of coil turns is large.

In the above configuration, the coil may be wound at least two sides of the stator.

The coil is wound around two sides of the rectangular-shaped stator, thereby increasing the number of coil turns.

In the above configuration, the rotor is located at a center portion of one side of the stator, and the coil is wound around two opposing sides of the stator.

This configuration can also increase the number of coil turns.

In the above configuration, the rotor may be located at a corner portion of the stator, the coil may be wound around two sides of the stator, and the two sides do not oppose to each other.

This configuration can also increase the number of coil turns.

In the above configuration, the stator may have a flat shape in an optical direction.

This configuration can maintain the reduced thickness in the optical axis direction.

In the above configuration, the stator may include a plurality of iron pieces mutually connected, and each of the plurality of iron pieces may have a thin portion thinner than another portion at a connecting portion where the plurality of iron pieces are connected to each other.

With such a configuration, the plural iron pieces are connected at their thin portions, thereby maintaining the reduced thickness in the optical axis direction.

In addition, in a case where a stator is integrally formed and has a complicated shape to surround the periphery of the opening, the workability of winding a coil around the stator may be difficult. However, since the stator is composed of the iron pieces connected, the coil is wound around any of the iron pieces before the iron pieces are connected. Then, the iron pieces are connected to improve the workability in winding a coil.

In the above configuration, the blade may be positioned at a receded position receded from the opening with overlapping the stator in an optical axis direction.

This maintains the reduction in size in the planar direction.

In the above configuration, the coil may be wound around at a position where the stator does not interfere with the blade positioned at the receded position.

This maintains the reduction in size in the planar direction.

In the above configuration, a control IC for controlling energization of the coil may be mounted on the printed substrate, and the control IC may be housed in the chassis and surrounded by the stator.

With such a configuration, the blade drive device and the control IC can be unitized and its handling can be facilitated. Further, a space in an external device equipped with the blade drive device can be effectively used. 

1. A blade drive device comprising: a blade; a drive source that drives the blade; and a chassis that has an opening opened and closed by the blade and that houses the blade and the drive source, the drive source comprising: a rotor that is rotatably supported; a stator around which a coil for excitation is wound and which applies a rotational force to the rotor, and the stator being arranged to surround a periphery of the opening and having a rectangular shape.
 2. The blade drive device of claim 1, wherein the coil is wound at least two sides of the stator.
 3. The blade drive device of claim 2, wherein the rotor is located at a center portion of one side of the stator, and the coil is wound around two opposing sides of the stator.
 4. The blade drive device of claim 2, wherein the rotor is located at a corner portion of the stator, the coil is wound around two sides of the stator, and the two sides do not oppose to each other.
 5. The blade drive device of claim 1, wherein the stator has a flat shape in an optical axis direction.
 6. The blade drive device of claim 1, wherein the stator comprises a plurality of iron pieces mutually connected, and each of the plurality of iron pieces has a thin portion thinner than another portion at a connecting portion where the plurality of iron pieces are connected to each other.
 7. The blade drive device of claim 1, wherein the blade is positioned at a receded position receded from the opening with overlapping the stator in an optical axis direction.
 8. The blade drive device of claim 7, wherein the coil is wound around at a position where the stator does not interfere with the blade positioned at the receded position.
 9. The blade drive device of claim 1, wherein a control IC for controlling energization of the coil is mounted on the printed substrate, and the control IC is housed in the chassis and is surrounded by the stator. 